Health

Melatonin - the hormone of darkness

Article Abstract:

Melatonin is a hormone synthesized and secreted by the pineal gland in response to darkness. Melatonin secretion is higher at night and decreases significantly with age. Increased melatonin secretion decreases sexual activity in animals during winter. Delayed sexual maturation in children with tumors of the pineal gland may also be caused by increased melatonin secretion. A research study found increased blood levels of melatonin in a man with hypogonadism, or decreased activity of the gonads, and calcification of the pineal gland. Function of his pituitary gland and his gonads became normal after his blood levels of melatonin decreased. Both the patient's hypogonadism and calcification of his pineal gland may have been caused by the same underlying disorder.

Entrainment of free-running circadian rhythms by melatonin in blind people

Article Abstract:

Melatonin may help blind people sleep better because it puts their body on a 24-hour schedule, according to a study of seven blind people. Most blind people have a slightly longer schedule, which can cause insomnia and daytime sleepiness. Melatonin is a hormone produced by the pineal gland inside the brain.

Melatonin, circadian rhythms, and sleep

Article Abstract:

Studies in blind people show the melatonin is a component of the sleep-wake cycle. Melatonin is a hormone produced by the pineal gland in the brain. A study of blind people showed that melatonin could regulate their sleep-wake cycle, preventing insomnia.